This invention relates to improved burner apparatus for burning a mixture of flammable vapors and air.
There are various types of situations in which it may become desirable to burn a mixture of flammable vapors, such as gasoline vapors, and air, which mixture may under at least some operating conditions be extremely lean and thus difficult to burn in a conventional burner arrangement, or which may vary under different operating circumstances from such a lean condition to a relatively rich condition of vastly increased B.T.U. content. One such situation is in apparatus such as that shown for example in U.S. Pat. No. 3,897,193 in which gasoline vapors are collected from the vicinity of a dispensing nozzle while fuel is delivered through that nozzle into a vehicle tank or other tank at a service station. The vapors thus collected may at some times be in a very lean mixture with air, particularly where as in that patent some of the vapors may initially be collected on an adsorbent bed and then subsequently desorbed from that bed by drawing a reverse flow of air through the bed to remove the vapors for delivery with the air to a burner. During the final stages of such a desorption process, the amount of flammable vapors present in the adsorptive bed may be very limited, so that the ultimate overall vapor-air mixture produced by movement of air through the bed is extremely lean and difficult to burn in a conventional burner.
Other situations in which it may be desired to burn a very lean vapor-air mixture include for example sewage disposal installations in which methane gas may be produced but at a relatively low rate or concentration with respect to the amount of air present in admixture with the gas. Unless that flammable gas can be burned, it may be necessary to utilize relatively expensive catalytic or other recovery equipment for preventing polluting escape of the vapors into the atmosphere.